不同饲料营养对母牛繁殖力影响效果分析

通过对妊娠后期母牛(后142 d)、带犊哺乳母牛的不同阶段饲料营养搭配和犊牛早期补饲、早期断奶试验,研究探讨缩短母牛产后空怀时间,促进母牛产后早期发情配种,提高母牛繁殖率的经济有效技术方案。1材料与方法1.1试验牛的选择和分组选择健康无病,发育正常,营养状况良好,年龄3~8岁,产犊2~5岁,且已怀胎4.5~5.2个月的晋南牛母牛36头,随机分为试验1组、试验2组和对照组3个不同组合,每组各12头。待母牛产犊后,进入试验阶段,分组不变。1.2试验牛的饲养管理试验牛在相同环境条件下饲养,最后饲养在1个或相近的2~3个村,环境条件大致相同,每个试验组合…     

早期断奶后备母牛繁殖效果研究

选择后备母牛１８头，每组各６头，采用不同的日粮饲喂，进行对照试验，结果试验１组后备母牛初情月龄平均为１０．３个月，第一、二情期受胎率８３．３％，繁殖成活率８３．３％。试验２组后备母牛初情期平均为１１．１个月，第一、二情期受胎率６６．７％，繁殖成活率６６．７％。对照组后备母牛初情期平均为１２．７个月，一、二情期受胎率５０．０％，繁殖成活率５０．０％。     

奶牛产后恢复生殖机能Markov过程分析

作者对随机分组实施奶牛产后早期生殖机能障碍综合防制措施的实验组１５２头母牛和同群常规饲养的对照组１５１头母牛，选定产后４５，６０，８５，１００，１２０ｄ等５个时点，依不孕母牛（Ｓ１）暂时牛恢复正常性周期母牛（Ｓ２），恢复正常性周期暂未配孕母牛（Ｓ３），已配孕母牛（Ｓ４）作恢复生殖机能状态演变过程分析，本文采用有吸收点的Ｍａｒｋｏｖ模型，通过４种状态在不同时点演变过程的转移概率矩阵计算，得出各间隔时     

稀土饲料添加剂饲养绵羊的剂量选择试验

选用半舍饲的周岁龄青海细毛羊５６只，分为三组，试验１、２组各２０只，对照组１６只。在同等饲养管理条件下，试验１、２组每只羊每日分别添加０．２ｇ和０．１ｇＲＣＦ－３稀土添加剂，进行６０ｄ饲养试验。结果：试验１、２组绵羊平均日增重分别比对照组提高３０．６％（Ｐ＜０．０１）和１２．６％（Ｐ＞０．０５）；平均羊毛长度分别比对照组提高２２．１％（Ｐ＜０．０１）和５．５％（Ｐ＞０．０５）；经济效益分别比对照组提高２５．２％（Ｐ＜０．０１）和８．７％（Ｐ＞０．０５％）。试验１组平均日增重，羊毛长度和经济效益分别比２组提高１５．９％（Ｐ＜０．０５）、１５．７％（Ｐ＜０．０５）和１５．２％（Ｐ＜０．０５）以试验１组的效果为佳。     

补料对哺乳犊牛生长性能的影响

选用泌乳性能中等的当地母牛１５头和其平均出生日龄１１５天的利木赞杂一代哺乳公犊１５头。母，子牛自由采食青贮玉米结，犊牛补料配方为两种全价饲料，经７３天，补料试验，两个补料的试验组的平均日增重均显著高于不补料的对照组，其中试验１组平均日增重０．８２３ｋｇ，试验２组０．７９２ｋｇ。试验１组的平均总增重比对照组多２４．６５ｋｇ，试验２组则多２２．４５ｋｇ；试验１组的平均每ｋｇ额外增重所耗饲料２．７７ｋｇ     

应用促排卵三号生殖激素治疗母牛排卵障碍试验报告

在承德市丰宁县五通营十七道沟村和撒岱沟门村各选繁殖力正常的母黄牛７０头,分别作为试验组和对照组,两组牛均正常参加配种。试验组母牛在产后３０天肌注促排卵３号１支（２００ｍｇ）对照组母牛不作任何药物处理,两组牛饲养管理条件完全相同,用药后第３天输精,输精后６０天和９０天分别进行妊娠,结果表明：两次妊娠试验组分别比对照组母牛受胎率提高１４．３％和４４．３％,效果显著。     

大黄鱼湿颗粒饲料的研究初报

通过对大黄鱼投喂湿颗粒饲料和小杂鱼的饲养对比试验,初步确定了大黄鱼湿颗粒饲料中干粉料的营养成分和所用原料。成鱼组经过７７ｄ 的饲养,投喂湿颗粒饲料的试验组和投喂小杂鱼的对照组尾平均日增重分别为１．４９ｇ 和１ ．２６ｇ , 饲料系数分别为３ ．８７ 和７．３０ ; 幼鱼组经过１６４ｄ 的饲养,试验组和对照组尾平均日增重分别为０ ．６４ｇ 和０．４６ｇ ,饲料系数分别为２．３８ 和４ ．８５ 。大黄鱼增重１ｋｇ 所需饲料成本成鱼试验组比对照组可节约１．７２ 元,幼鱼试验组比对照组可节约２ ．１７ 元。     

蚕沙喂猪效果试验

１　材料与方法１．１　试验猪　选择大×本杂种商品猪,第１期（肥育前期）４０头按性别、体重随机分为２组,每组分２栏饲养,每栏１０头,组间体重相近,试验期７５天;第２期（肥育后期）４０头分为２组,每组分２栏饲养,每栏１０头,组间体重相近,试验期６０天。１．２　饲粮组成　基础日粮用本县饲料公司生产的配合料,按参试猪的不同生长阶段,第１期用中猪料,第２期用大猪料。试验组第１期基础日粮９０％、蚕沙１０％;第２期基础日粮８５％,蚕沙１５％;对照组基础日粮１００％。１．３　饲料营养水平　第１期每１ｋｇ基础饲料…     

塞曼特罗（CIM）对猪的生长,胴体组成和营养分代谢的影响

选用２４头杜二杂种猪和３２头大二杂种猪（试验２）进行日粮添加ＣＩＭ１μｇ／ｇ试验。试验１和２试验期分别为２８ｄ和２０ｄ。其中ＣＩＭ组的平均日增重分别较对照组提高１５．７％和１２．９％，粒重比分别降低１３．３％和１０．０％。     

小肽制品喂大快对断奶仔猪生长的影响

选择日龄、体重相近的三元杂交仔猪６０头,随机分为３组：即对照组。试验１组和试验２组,每个组各设置２个重复。经过２９ｄ试验,试验结果表明：试验组与对照组相比增重差异极显著（Ｐ〈０．０１）,组内差异不显著（Ｐ〉０．０５）。试验１、２组平均日增重比对照组分别提高７．８５％,８．８５％（Ｐ〈０．０１）;饲料转化率分别提高１０．６０％、１１．０６％。从腹泻情况看,饲用喂大快组仔猪痢头数明显少于对照组。     

BMY牛提前产犊试验

[目的]为提高母牛的利用年限、缩短后备母牛的培育时间、探索BMY青年牛的适配年龄（体重）和提前妊娠产犊对母畜和犊牛的影响。[方法]对断乳母犊进行适当培育,使其早进入初情期,运用繁殖生物技术妊娠产犊。[结果]经过培育后BMY青年牛的初情期平均为（270.8±20.8）d,此时的平均体重为（254±10.6）kg,发情周期...     

Calving system and weaning age effects on cow and preweaning calf performance in the Northern Great Plains

A 3-yr study evaluated late winter (Feb), early spring (Apr), and late spring (Jun) calving systems in conjunction with varied weaning strategies on beef cow and calf performance from Northern Great Plains rangelands. Crossbred cows were randomly assigned to one of three calving systems (on average n= 168.calving system(-1).yr(-1)) and one of two weaning times (Wean 1, 2) within each calving system. The Feb and Apr calves were weaned at 190 and 240 d of age, whereas Jun calves were weaned at 140 and 190 d of age. Breeding by natural service occurred in a 32-d period that included estrous synchronization. Cows were managed throughout the year as appropriate for their calving season. Quantity and quality of hay and supplements were provided based on forage and weather conditions, physiological state of the cows, and available harvested feed resources within a year. After weaning, two-thirds of the early weaned steers were fed in confinement in Montana, and one-third were shipped to Oklahoma and were grazed or fed forage. One-half of the early weaned heifers grazed seeded pastures, and the other half was fed in confinement. Early weaned calves were weighed on approximately the same day as late-weaned calves. Birth weight and overall rate of gain from birth to weaning did not differ for calves from the three calving systems. Calf weaning weight differed by weaning age within calving system (P = 0.001), and calves from the Jun calving system that were weaned at 190 d of age tended (P = 0.06) to be lighter than calves of the same age from the Feb or Apr calving systems. Cow BW change and BCS dynamics were affected by calving system, but the proportion of cows pregnant in the fall was not. Cows suckled until later dates gained less or lost more BW during the 50 d between the first and second weaning than dry cows during this period. The previous year's weaning assignment did not affect production in the following year. Estimated harvested feed inputs were less for the Jun cows than for the Feb and Apr cows. We conclude that season of calving and weaning age affect outputs from rangeland-based beef cattle operations.     

奶牛胚胎分割试验研究

简单分割7～8天奶牛胚胎59枚(117个半胚)。裸半胚成对移给59头奶牛或黄牛,80～90天有27头(45.8％)妊娠。最后24头受体产犊34头,半胚产犊率29.1％(34/117)。有10对双胎,双胎率41.7％(10/24)。比较在不同情况下—7天或8天;晚桑椹或囊胚期;透明带软化处理或不软化处理—分割的半胚,成对移植后受体妊娠率分别是40.0％和57.9％;35.7％和54.8％;48.6％和41.7％。半胚产犊率分别是26.6％和34.2％;23.6％和33.9％;30.0％和27.7％。均无显著差异(P>0.05)。分割优质胚胎得到最好的(35.7％)半胚产犊率。半胚在体外5小时内移植有较高(30.5％)的产犊率。试验探索了奶牛半胚移给远处分散的农户黄牛的可能性。11对奶牛半胚移给11头黄牛有6头(54.5％)妊娠。最后5头受体产下7头奶牛犊,两对同卵双胎。     

Cow breeding and calf growth performance as affected by pregnancy status the previous year

A 2-yr study was conducted to compare the subsequent cow breeding and calf performance of cows that were nonpregnant with cows that were pregnant at the time calves were weaned. Cows were Angus (A), Polled Hereford (PH), Santa Gertrudis (SG) straightbreds and crossbreds of these breeds. Nonpregnant cows (G1) were 4- to 9-yr-olds that had a calf the previous year and appeared to be physically sound with no detection (by rectal palpation) of an abnormal reproductive tract due to disease, abnormal growth or calving difficulties. Pregnant cows (G2) were of similar age and breed composition to G1 cows. The 93 G1 and the 193 G2 cows were assigned within age and breed composition to sire breeding groups on pasture in an approximate 1:2 ratio, respectively, per sire. There were six A, three PH and one SG sires. The year prior to G1 cows being nonpregnant, G1 cows calved 11 d later (P less than .01) than G2 cows. Subsequent to their being nonpregnant, G1 cows gained 27 kg more (P less than .001) weight during the breeding period, had 5.4 percentage units more (P less than .29) calves born, had calves 17 d earlier (P less than .001) in the calving period, had calves that gained at a similar rate to weaning and had calves that were 14 kg heavier (P less than .01) at weaning (due to their being 17 d older) compared with G2 cows and calves.     

Effects of age on body condition and production parameters of multiparous beef cows

Pregnancy rate, calving interval, birth weight, weaning weight, and quarterly BCS were collected for 5 consecutive years on 454 fall-calving multiparous British crossbred cattle (3 to 10 yr of age) to evaluate associations of age with BCS and production parameters. Body weight and BCS were collected pre-calving, prebreeding, at weaning, and midway through the second trimester of pregnancy (August). Body condition score was correlated with age during all seasons (P < 0.01). At calving, breeding, and in August, 3-yr-old cows had the lowest BW and BCS, whereas 8-yr-old cows had the greatest. At weaning, these values were maximal in 10-yr-old cows. Pregnancy rate was near 80% up to 9 yr of age but decreased to 57% in 10-yr-old cows. The relationship of pregnancy rate with age appears to be correlated with the BCS decrease at breeding in the older cows, supported by the fact that inclusion of BCS at breeding in the statistical model eliminated the effect of age on pregnancy rate (P = 0.42). Calving interval was longer in 3-yr-old cows compared with 4- to 9-yr-old cows (P = 0.02); however, among older cows, there was little change in the calving interval. Birth weight reached a maximum at 8 yr of age (35 +/- 0.9 kg) and a minimum in 3-yr-old cows (32 +/- 0.7 kg). Birth weights of calves born to both 3- and 4-yr-old cows were lower than for those born to 5-, 6-, 7-, or 8-yr-old cows (P < 0.05). Ten-year-old cows weaned lighter calves (205-d adjusted weaning weight) than younger dams. Furthermore, 3-yr-old cows weaned calves 9 +/- 2.1 and 14 +/- 2.4 kg lighter than 4- and 5-yr-old cows, respectively (P < 0.001). Interpretation of the age analyses of calving interval, birth weight, and weaning weight was independent of the inclusion of BCS in the model. This study documents the effects of age on calving interval, birth weight, and weaning weight that are independent of BCS.     

Effects of breeding season length and calving season on range beef cow productivity

A 5-yr study was conducted beginning in 1983 with 460 cows to evaluate the effects of three breeding seasons (30, 45, and 70 d in length) and two times of spring calving, March (early) and April (late), on cattle production under Nebraska Sandhills range conditions. Criteria evaluated included pregnancy and weaning percentages, calving date and distribution, cow weights and body condition at four intervals, calf birth and weaning weights, and cow productivity. The 30-d breeding season included a 10-d estrus synchronization and AI period; in the other breeding seasons only natural breeding was used. The same sires were used over the entire study period. Percentage of cows pregnant and percentage of calves weaned were lower (P less than .01) for cows bred for 30 d than for cows bred for 45 or 70 d. Average calving dates were similar among the breeding groups within the early and late calving herds. Pregnancy rates from AI were higher (P less than .01) for the cows calving in April (64%) than for the cows calving in March (41%). Cows calving in April lost less weight between precalving and prebreeding and were heavier (P less than .05) at prebreeding time than the cows calving in March. Calf weaning weights were not different (P greater than .10) among any of the breeding season groups or between the two calving herds when calves were weaned at a similar age. Cow productivity (calf weaning weight per breeding female) was highest (P less than .05) for the cows bred for 70 d (186 kg), intermediate for the cows bred for 45 d (172 kg), and lowest for cows bred for 30 d (162 kg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of Pre- and Post-Partum Feed Supplementation on the Productive and Reproductive Performance of Grazing Primiparous Brahman Cows

This experiment studied the combined effect of pre- and post-calving feed supplementation on the productive and reproductive performance of primiparous Brahman cows. The animals were 4 years old (420 kg live weight) and pregnant, and grazed rotationally on Stargrass (Cynodon nlemfuensis) pastures. Supplementation was given before and after (T1, n = 15), only before (T2, n = 15) or only after (T3, n = 16) calving, and there was an unsupplemented control (T4, n = 16). The supplement (1.5 kg/animal per day, 13.4 MJ digestible energy/kg dry matter and 20% crude protein) was given for 45 days before and/or after calving. Changes in body weight and body condition score and the productive behaviour of the calves were similar (p>0.05) among treatments. The concentration of urea in the plasma was low in the control group (T4) before and after calving. The animals in all the groups had a poor reproductive performance. The percentage of cows in oestrus was higher (p<0.05) in T1 (73.3%) than in T3 (37.5%). The interval from calving to conception (148.7±53.7 days) and the pregnancy rate (48.5%) were similar (p>0.05) among the treatments. The level of supplementation offered before and/or after calving did not improve the pregnancy rate.     

使用PMSG等激素提高四川黄牛繁殖效率研究再报

在初报基础上改进用药方法、扩大试验规模到２４头。发情率９５．８％，总受胎率７０．８％，得一胎孪生牛；校正后的产Ｄｕ间隔以对照组有显著缩短。该处理方法在缩短空怀期、治疗屡配不孕等方面表现了良好作用。重点讨论了该方法的适应范围、对动物选择的要求，以及处理后再发情时间与受孕效果的关系。     

Induction of parturition in dairy cattle and its effects on health and subsequent lactation and reproductive performance

OBJECTIVE: To determine the effect of induction of parturition on health, milk production and reproductive performance of dairy cows. DESIGN: A prospective cohort study in 62 dairy herds. PROCEDURE: Health, milk production and fertility indices were documented for 1449 dairy cows treated with dexamethasone trimethylacetate, with or without prostaglandin to induce calving. Equivalent data was collected for 603 untreated herd mates that calved at approximately the same time. RESULTS: The median interval from initial treatment to calving was 11 days. Induction was associated with a substantially lower calf survival and commercial value of surviving calves. Calf viability and value was lower when induced cows were at an earlier stage of pregnancy. Retained foetal membranes, photosensitisation and other problems were significantly more frequent in the induced group compared to the untreated group. Milk production of induced cows was approximately 4% lower than untreated ones, but the majority of reproductive indices were not significantly different between the two groups. CONCLUSIONS: The practice of induction of parturition in seasonal calving dairy herds is a reliable way of shortening the gestation period of cows. Costs associated with morbidity and mortality of induced cows and losses in lactation and calf production are offset by benefits of improved reproductive performance and more efficient management of the herd. The welfare aspects of induction on calf survival must be considered.